Process for treating tobacco material and apparatus therefor



Spt. '15, 1931;

R. e. MEWBORNE PROCESS FOR TREATING TOBACCO MATERIAL AND APPARATUSTHEREFOR File l Dec. 26, 2 2 Sheets-Sheet -1 INVENTOR 65% fi/ g BYKTTORNEY Sept. 15, 1931. R. G. MEWBORNE 1,823,554 PROCESS FOR TREATINGTOBACCO MATERIAL AND APPARATUS T HEREFOR' Filed Dec. 26, 1925 2She'ets-Sheet 2 INVENTOR BY Oi ATTORNEY Patented Sept. 15, 1931 UNITEDSTATES ROBERT GRAHAM MEWBORNE, OF ALBUQUERQUE, NEW MEXICO, ASSIGNOR TOCON- PATENT OFFICE SUMERS TOBACCO COMPANY, INC, 013 ALBUQUERQUE, NEWMEXICO, A CORIPORATION OF DELAWARE PROCESS FOR TREATING TOBACCO MATERIALAND APPARATUS THEREFOR Application filed December 26, 1925. Serial No.77,711.

This invention relates generally to a process fortreating tobaccomaterial to recover the nicotine content thereof and to new novelapparatus for carrying out the same. The invention is more particularlydirected to the treatment of tobacco material in the various formsthereof or any or all parts of the plant in various forms, including thestalks, leaves or roots of the tobacco plant as grown, or varions wasteproducts of the plant of any tobacco industry. The invention is moreparticularly directed to the treatment of tobacco for recoveringnicotine or similar alkaloidal, volatile constituents in an extractiveagent, for the purpose of production of nicotine in its various forms,either as free nicotine, nico-- tine solutions or nicotine salts orcompounds.

As the nicotine content thus far known is contained in the tobaccomaterial in chemical, physical or mechanical combination with the acidsor resinous, albuminous materials of the plant or the plant cells, infairly stable condition, an ini ial treatment is first resorted to, tomake the nicotine available for further processing by freeing thenicotine from its combination of plant constituents by treatment withalkaline materials, al though, in some instances, where the nicotine isalready freedue to fermentation or otherwisethis initial treatment withan alkali is unnecessary. The reaction of alkalies upon the tobaccomaterial frees the nicotine as an alkaloid which'remains in $01? tionwithin the/reaction products and the other constituents of the plant andis known as free nicotine and, in this connection, my Y invention isdirected to that type ofprocess which recovers the nico ine so freedfrom this heterogeneous mass by an extractive agent in the vapor formwhich, as it passes from the mass serves to entrain, entrap, vaporize ormechanically carry off the nicotine for subsequent recovery bycondensation or other sui able methods,

As hitherto practiced, nicotine has been separated from the plantcontaining thesame by distillation, use being made of an extractiveagent to volatilize the nicotine from the tobacco material which hasbeen previously treated to free the same from the acid constituents,resinous gums, albuminous materials or the like in the plant cells, inoriginal combination with nicotine. The nicotine, once liberated fromchemical, physical or mechanical combination with the original plantconstituents, is subjected to heat treatment to volatilize the nicotineand for economy of cost and efiiciency of processing, particularly wherewater has been used as the solute for the initial alkaline treatment,steam has been used as the extractive agent.

With the tobacco material thus far used, the processes for the recoveryof nicotine contended with a nicotine content of less than 4% and wheresteam or water and heat necessar to create the steam were used to carry0 the nicotine products, a quantity of steam which when in the form ofwater ousyalbuminous, gummy or other component present in tobacco, as isfound or may occur in tobacco material having a content upwards of 4%.

Where I have attempted to recover nicotine from tobacco materialcontaining nicotine in excess of 4% by a water component equivalent to 4pounds of water to 1 pound of tobacco, I have found that a totalliberation of the nicotine cannot be effected, nor,

where I have attempted to increase the temperatures for carrying out theprocess of recovering nicotine from tobacco carrying nicotine in excessof 4%, have I been able to effect the separation because of the highresinous, gumn'ly, albnminous or other components found in the tobaccoplant of this nicotine con stitutiou so that, while ordinarily thenicotine will be volatilized to a degree in which the temperatures areraised, the effect of heat on the components not desired in the plantare adversely affected to entrap the nicotine components beyond thecondition where the nicotine content can be economically separatedtherefrom. WVhile where I have attempted to supply an amount of water atone time to supply vapor sufficient to carry off the nicotine ofpercentages in excess of 4%, the resinous, gummy, .albuminous and otherconstituents of the plant are dissolved to such an extent as to furtherinterfere with the liberation of the nicotine and to make it impracticalfor a continuous process, particularly where heating elements areemployed to liberate the steam by coating the heating elements orproducing a froth, making it necessary to discontinue the process tocleanse the heating elements or remove the batch from the distillingchamber. Thus, any attempts to increase the quantity of extractiveagent, such as water, have been found to adversely afiect the physicalcharacteris tics of the batch, whereas where I have used hightemperatures, the plant components are affected to further serve toentrap the desirable constituents beyond economical recovery.

31y invention, therefore, has for an object thereof the provisionofaprocess for recovering the nicotine from tobacco material by the use of.an extractive agent in quantities sufficient to carry ofi' the nicotinecontent without adversely affecting the physical characteristics of thematerial treated so that high economy of cost and efficiency ofoperation may be obtained to completely recover nicotine as present intobacco material in any quantities, more particularly with a nicotinecontent tobacco ration above 4% and as high as 10%. 7

My invention further has for an object thereof, the provision of aprocess for recovering nicotine from tobacco material,.including thathaving a nicotine content of as high as 10% in which water or its vaporsare used as the extractive agent in quantities suflicient tocharge thetobacco to its highest absorptive power, without interfering withconditions which are most conducive for liberating the nicotine andwithout imparting to the product treated physical conditionsobjectionable for treating the product continuously, due to the adhesiveagents present in tobacco besides nicotine, such as resins, albuminousmaterials, gums or the like, the process involving the liberation ofnicotine from a condition in which it will be'more completely carriedoff when in contact with. or

thereof the provision of a process for extracting nicotine from tobaccomaterial, using water vapor as the extractive agent and maintainingconditions wherein the tobacco material is always in contact with, andhas present a quantity of water sufficient to dissolve the nicotinecontent so that the nicotine that carried ofi by the vapors generatedwill be effectuated at conditions, so far as possible, when waterchanges from the liquid phase to the vapor phase.

My invention still further has for its object the provision of a processin which water vapor is used .as an extractive agent and in which thereis always present an amount of water in excess of that which will besufficient to carry off the'nicotine component but below that at whichit adversely affects the adhesive components of the tobacco material tocause exudation of the adhesive material to wad the batch and interferewith separation in an apparatus in which the process is to be carried oncontinuously.

My invention further has for an object thereof the provision of aprocess controlled as to temperature and time of reaction so that use ismade, to the maximum degree possible of heat transference when water,changes from the liquid phase to the vapor phase, and from the vapor tothe liquid phase, conditions being maintained such that there isalternately effected aheating of the tobacco material to liberatequantities of water vapor to carry off nicotine and then to a cooling inthe presence of water vapor to condense an amount of water necessary forliberation of the nicotine in solution, and the absorption of heat unitsaccompanying condensation to more efficiently raise the temperature ofthe nicotine so that upon again heating the mass, a maximum amount ofsteam will be generated under conditions carrying off the highest degreeof nicotine.

The invention further has for an object thereof the provision of aprocess in which tobacco material is maintained in the presence of anextractive agent in the liquid phase in amounts suflicient to dissolvethe nicotine content while maintaining conditions as to temperature sothat the nicotine will more completely pass into the vapor form and thisI accomplish by always maintaining the tobacco material treated with aquantity of watersufficient to dissolve the nicotine content andmaintain the batch at a temperature at which steam is generated, andsurrounding atmospheric conditions being maintained such as to carry offthe nicotine liberated by charging the atmosphere with a quantity ofwater in the liquid phase and alternating the temperature conditionsfrom an upper limit to liberate steam and carry off nicotine, and to adiminished temperature to rewet or condense a portion of the vapor uponthe tobacco material undergoing treatment.

My invention still further has for an obor close to the criticaltemperature for gen-' erating steam.

My invention may be considered as providing a process for obtainingnicotine beginning with tobacco which is so wet as to completelydissolve the nicotine content, but so dry as to .be cap-able ofprocessing without interfering mechanically in the apparatus used, theprocess including a series of drying and rewetting steps, the drying tocarry oil an amount of nicotine and the wetting to resupply watersufficient for solution of the nicotine content, further conditionsbeing maintained during the process that the rewetting is ca-rried onfrom the extractive agent used or under conditions that a rewetting iseffected in proportion to the nicotine content and without interferingwith the physical characteristics of the. material treated necessary fora continuous operation. .There is further provided atmosphericconditions surrounding the zone in which the nicotine is evolved andsubjected to a movement in the direction to carry away the desirablecomponent in a vapor phase, comprising an extractive agent including anamount thereof in a liquid phase so as to be able to carry a quantity ofnicotine higher than that which a I vapor would normally carry andmaintaining a vapor pressure conducive to a more rapid generation of thenicotine from the tobacco material. In the more particular embodiment,my invention provides an extractive agent in the vapor form; such asstem, carrying with it a proportion of water in the liquid phase which,moving counter-currently to the tobacco material that is heated so as togenerate nicotine vapor, will carry a higher amount of nicotine, thenicotine generatedunder these conditions serving to dissolve to someextent in the water in the liquid phase and producing a condition ofvapor pressure, accelerating the generation of nicotine at the hotterportions of the apparatus.

Other objects of my invention reside in new and novel apparatus forserving etliciently to carry out my process and attain the objects abovementioned.

To attain these objects and such further objects as may appear herein orbe hereinafter pointed out, I will now refer to a more detaileddescription of a preferred embodiment of my invention.

Tobacco material, preferably containing upwards of 4% of nicotine and ashigh as 10%, or even in excess ,tl1ereof, including any or all parts ofthe tobacco plant, are used as the source for the nicotine. This tobaccomaterial is preferably broken into small particles ranging from dust orparticles of finer size to lumps from 1 to 2inches in diameter. However,any form of the plant will serve the purpose in the process Whichwillnow be outlined.

The initial step is to treat the tobacco material to liberate, should.it'not already be free, the nicotine content from its combina tion withthe resins, gums, albuminous materials or plant cells by a treatmentwith an alkali solution such as the hydroxides or carbonates of thealkali metals, as sodium, or the hydroxides ofthe alkali earths, such ascalcium.. Preferably a lime paste is added containing 10 to 20% of limein proportions amounting to 2 to 4 parts of this mixture to 1 pound oftobacco. The variations in quantity'of the lime mixture added will bemadc, depending upon the character of the tobacco, that is, where a highmoisture content tobacco is used the amount will be diminished, whereaswhere a drier tobacco is used the amountmay be increased towards theupper limit. However, the amount added should ,never be in excess ofthat where there will be by suitable mixing apparatus has been effectedis: The operator can determine approximately the proper condition bypressing a handful of the material. The amount of water should never bein excess of that which will cause the tobacco to Wad or chunk butshould have the property of again becoming fluffy, upon the release'ofthe pressure.

The mixture thus prepared is introduced into a heating chamberprovidedwith suitable heating and mixing elements to expose.

the material fed thereto to proper heating operation and serves to movethe material fed thereto continuously. The heat is sutlicient togenerateflsteam within the mass and carry with it the nicotine containedtherein. As the generation: of the steam progresses, the vapors areremoved couliter-currently by some suitable suction device. at the sametime drawing along with it a quantity of an extractive agent, such assteam. which preterably carries entrained therewith a. suspension ofwater.

, The heating arrangement is such that there is an alternate exposure ofthe tobacco material to a maximum temperature and then a III) movementof the material so treated to a cooler zone, all being carried outwithin an atmosphere of' the extractive agent in vapor charged withsmall particles of water in the 5 form of a spray, fog or mist. As thetobacco material is exposed to the heat of the hottest portion of thechamber, steam is generated that will volatilize the nicotine, at thesame time serving to dry the tobacco, to some extent. The tobaccomaterial is then alternately directed to the cooler portion of theheating chamber where, coming in contact with the extractive agent,there is deposited thereon by absorption or condensation a small amountof water supplying an amount less than but almost as much as that lostat the previous heating but to an extent sufficient to further keep insolution the nicotine content. The tobacco material is then againexposed to the hotter portion of the heating chamber where again anamount of steam is generated within the wet mass to carry with it afresh quantityof nicotine. The speed of. operation is maintained suchthat when exposed to the hotter portion of the heating chamber, it willnot become so hot that upon entering the cooler portion of the heatingchamber it will cause undue transference of heat to the extractiveagent, for example, steam containing dispersed water, but will so enterthe cooler zone as to be able to condense and absorb an amount oftheextractive agent, such as water, in proportion to the nicotineremaining in the tobacco material and retain it in solution. 1

The process continues so that the tobacco material becomes drier as thenicotine content extracted andbecomes less and, as previously stated,the speed of operation is such that as the nicotine content becomessmallerfthere is a smaller amount of water absorbed, at each stage ofthe treatment of the material within the cooler zone.

In the more ,particular embodiment of my invention, as practiceth'thehottest portion of the heating elements is maintained such that it willbe just suflicient to generate steam within thewet mass while the coolerportion is maintained just short of that where, comi'ng in contact withthe vapor, it will transfer the heat thereto but just below that whereit will cause condensation of a portion of the vapor thereon. Thus, itwill be observed that the hottest zone of reaction is just about 212 F.so as to generate steam within the alkaline material while the coolerzone is just below 212 F., where it will absorb or condense an amount ofthe extractive agent with whichit is in contact.

This process may be carried out in various ways but for my purpose theapparatus diato disclose certain details. Figure 2 is a section taken ona line 22 of Figure 1. Figure 3 is a section taken on a line 33 ofFigure 1.

In the drawings, 10 is a drum or chamber of cylindrical form arrangedfor rotation by providing the annular tracks 11 and 12 near the endsthereof and resting upon rollers 13 and 14, supported in suitablebearings 15 and 16. Preferably, though not necessarily, the roller 13and bearing 15 are supported upon a block 17 to elevate this end of thedrum. There is provided at the front end of the drum 10 a stationaryduct 18 leading into the drum at its axial line and arranged forpermitting relative rotary movement thereof while being maintainedsealed by the annular nib 19 within the flange 20.

The duct 18 has its lower end provided with the supply and feeding unit21 for raw tobacco material. This unit comprises a mixing chamber 22having a tobacco entrance port or hopper 23 and an alkali solution orlime paste measuring device 24 leading into the same. Suitable mixingpaddles mounted on the shaft 25 are arranged for by the sprocket 26.Leading from the chamber 22 at one end thereof, is a cut flight screwconveyor 27 operated by the sprocket 28, and serves to feed the limedtobacco material to the duct, and allow a time for absorption ofextraneous water, complete chemical reaction with the alkali, at thesame time acting as a seal for the heating chamber. The upper end of theduct leads the vapors generated within the drum to suitable recovery andvapor cleansing apparatus, as the dust collector 29.

and then to the surface condenser 30, movement of the vapors in thedirection indicated being induced by the suction fan 31. The coolingwater supply for the condenser is shown at 32, whereas the condensatemay be collected from the outlet shown at 33.

Vithin the chamber 10 there is arranged heating elements or tubes 34 atthe periphery of the drum, in suitable numbers, all connected at theirends by the front manifold 36 and the rear manifold 37. A stationaryhead 38 is sealed by the annular gasket 39 and flange 40 at the axialline, permitting rotary movement of the drain.

Preferably, high pressure steam is used to supply the heat, and this isaccomplished at the axial line of the front manifold 37, through thepipe line 41 beyond the trap 41. within the housing 42 which serves asthe n'ieans of discharging the condensed steam or water from the tubesor manifold through the end head 38 and then out through the spout 43.

Radiallv disposed within the chamber are a series of lifting shelves 44.of triangular conformation. supported upon the tubes at the periphery bysuitable straps 45 and at their apex 46 upon the central shaft 47. Theshelves are arranged progressively in screwpitch fashion, overlapping tosome extent when considered in transverse section, with the rightangular edges 48' away from the direction of movement of the materialand with the angular or hypothenuse edge 48 of the shelves in thedirection of movement of the material, for purposes which willhereinafter be pointed out. Towards the exit end, and lying flush withthe end of the chamber, are discharge lifting shelves 49 radiallydisposed towardsthe axial line directly over a central stationary hopper50 mounted onthe stationary end-head 38. A conduit 51 leads from thehopper 50 to discharge outside the chamber. v

Also leadin through the stationary endhead 38 into the chamber 10 is anextractive agent feed line 52, preferably for exhaust or low pressurewet-steam, into which is led a needle valve 53for. adding additionalwater to the steam in the line 52, and is so positioned that the rush ofsteam will atomize or otherwise finely divide the water led thereinto.For certain purposes the exhaust steam from the spout 43 may be led intoline 52 by suitable piping, as will be readily understood.

The operation of the process in connection yvith the apparatus abovedescribed is as fol ows:

The raw tobacco material, including any or all parts of the plant in anysize whatsoever, prefierably ranging from fine dust to lumps of 1 to 2inches in diameter, is incorporated in the mixing chamber 22 to which isadded, by means of the liquid measuring device 24, an amount of limepaste (10, to 20% free lime) until a quantity ,equivalent to 2 to 4parts by weight have been added, This mixture of lime paste and tobaccomaterial is thoroughly stirred by means of the paddles on the shaft 25to thoroughl commingle the same, meanwhile adding a quantity of steam asan aid for chemical reaction, and also a nice control or adjustment ofwater content, by means of the steam line 22 at one portion of thechamber. This mixture is carried on for a time sufficient to cause thereaction necessary for liberating the nicotine from its combination withthe acid, resinous, albuminous or gummy constituents within the cells ofthe plant. It will be understood that this mixing may be done adjacentto the main drum .or in a suitable apparatus forming a separate unit.

From the mixing chamber the mixture of limed tobacco material is'fed tothe main drum 10 by the cut flight or ribbon conveyor 'on the shaft 28,through the stationary head at the lower end of the duct 18. The maindrum 10 is of a length sufiicientto carry the process to completion asthe tobacco material traverses from the entrance at 18 to the exit whentimed with a speed of rotation of 1 to 2. revolutions per minute. Theheating tubes 34 within the drum are brought to a proper temperature bythe steam led thereinto from the main line 41, high pressure steam beingused so that a temperature above 212 F. is

maintained sufiicient to volatilize water from the tobacco materialalkalined as previously mentioned. As the tobacco material falls withinthe space between the end of the chamber and the manifold 36, it ispicked up by the shelves 44, gradually and progressively moving itupwardly along the periphery of the drum, portions of the tobaccomaterial being held in contact with the heating tubes through part ofthe rotation, until after a shelf reaches the horizontal position,whereupon some of the material will gravitate radially towards the axialline, other portions of the tobacco material sliding off the edge 48 tocascade the same towards the bottom of the tube.

The material thus gradually lifted and dropped will form ridges oftobacco material throughout the length of the heating chamber 10 and, byreason of the screw-pitch arrangement of the lifting shelves and theslight tilt which is given to the chamber, the

tobacco material will, during the course of rotation, be traversed tothe end of the chamber by the progressive lifting and falling from theshelves to the bottom of the tube. As the material reaches the end ofthe tube, the vertical lifting shelves 49, forming pockets with the endof the chamber, will drop some of the material into the hopper 50'and bedischarged from the conduit 51 when the treatment is completed.

During the rotary movement of the main chamber 10, the suction fan 31 isput into operation to draw in vapors that may be evolved from-the zoneof reaction within the heating chamber 10, passing off through the duct18 and the dust collector 29 andf thence to the condenser 30 where thenicotine products are collected in connectlon with the condensed waterof the vapor evolved.

Non-condensable gases containing nicotine, 311111101113 and othervaluable substances are passed onto a vapor scrubber for recoverythereof.

Simultaneous with this operation there is introduced into the heatingchamber a quantity of wet steam through the conduit 52 which, during itsflow, entraps therein additional water from the needle valve 53. The

which water exists to some extent in the liquid phase.

of the drum and shelf, heating continues,

evolving at the same time an amount of water and nicotine vapor. As theshelf a proaches the horlzontal position, some of t e tobacco materialwill fall off. Other portions of it will be carried along until theshelf reaches a somewhat vertical position when other portions of thematerial will fall off or shower, so as to be cascaded transversely ofthe length of the heating chamber. Other quantities of the tobaccomaterial remaining on the shelf will slide radially towards the axis ofthe chamber. As the material reaches the center of the heating chamberand as it necessarily moves away from the hottest portion or heatingtubes, it will encounter'that part at the centerwhere there is anappreciable drop in temperature and, consequently will be cooledto someextent. On the axial line it will encounter some of the vapor introducedinto the chamber and some of the water in the finely dispersed form,absorbing or condensing portions thereof and'resupplying a portion ofthat lost by the previous heating portion. The temperature at the axialline is maintained suchas it will be just critical to generatethe steamand condensation of water.

Thus, the temperature at the central portion of the tube will be suchthat the tobacco material striking the cross flow of vapors, will notlose such quantity of heat units to generate any steam from the waterthat may be condensed or absorbed therein nor will it be so low as to beunduly wetted by the amount of steam condensed.

Further rotation of the chamber will finally deposit the material havingthis additional quantity of Water absorbed therein or condensed thereonto the bottom of the tubes, upon the hottest portion or heating tubes34, whereupon the cycle will begin again.

This progressive volatilization of steam, carryin with its nicotinevapor and subsequent a sorption or condensation of water,'

progresses in such a manner that there is at first a larger quantity ofmoisture absorbed as the content of nicotine remains high and thengradually as 'nico ine is separated from tne tobacco natcnal, \heproduct becomes hotter and absorbs less and less quantity of watir in poportion to the nicotine remaining in the material treated. It will thusbe noted that, at the exit end, as the material treated emerges withcomplete separation of nicotine, the water content will also almostcompletely be separated.

By undergoing a series of reheating and rewettin at the speed ofoperation described and within the temperature limits described, it hasbeen found that a tobacco material having a content of nicotine as highas 10% or even in excess thereof, can be ing an atmosphere which furtherhelps to accelerate the generation of the nicotine vapor. This isaccomplished by reason of the extractive agent being present in both theliquid and vapor phase and the liquid carried within the extractiveagent forming a solvent for any nicotine that may be generated, raisingthe possibility of further generating a quantity of nicotine vapor. Thisextractive agent in both the liquid and the vapor phase, can furthercarry more than the theoretical quantity of nicotine as compared withsteam in the pure vapor phase. Thus, not only have I provided conditionsfor the more rapid generation of nicotine vapors but I have providedmeans for carrying a larger quantity of nicotinewith the same amount ofextractive agent.

In the claims where I have stated that I produce an atmosphere in whichthe extractive agent is in the liquid and vapor phase, I mean to includethereby any extractive agent, whether water or an organic solvent ornicotine, and where I have stated that the extractive agent is in theliquid phase in finely divided form, I mean to include there by thatcondition of dispersion as may be characterized as a fog, cloud, vaporor spray.

Having thus described my invention and illustrated its use, what I claimas new and desire to secure by Letters Patent, is I 1. In the process oftreating tobacco material to remove its nicotine content which includesthe steps of alternately" exposing previously wetted tobacco material inthe presence of a vapor extractive agent to heating and cooling, varyingfrom an upper temperature limit suflicient to volatilize a portion ofthe water content and to a lower limit sufficient to condense and absorbportions of an extractive agent in contact therewith when cooled andmaintain it in liquid phase.

2. In the process of treating tobacco material to remove its nicotinecontent which includes the steps of alternately exposing previouslywetted tobacco material in the pres ence of a vapor extractive agent toheating and cooling, varying respectively from an upper temperature,limit suflicient to volatilize a portion of the water content and to alower limit sufficient to condense and absorb portions of an extractiveagent being in contact therewith when cooled and maintain it in liquidphase, the extractive agent having a movement relative to the tobaccomaterial to progressively remove the nicotine content thereof.

3. In the process of treating tobacco material to remove its nicotinecontent which includes the steps of intermittently exposing previouslywetted tobacco material having its nicotine content liberated bytreatment with an alkali, to heating while contacting the tobaccomaterial with an extractive agent, the heating varying from an upperlimit suificient to volatilize a portion of the water content and to alower limit sufficient to condense and absorb portions of the extractiveagent and maintaining the extractive agent at a temperature withinlimits to retain the same in the mixed vapor and liquid phase whilegiving it a'movement relative to the tobacco material to graduallyremove the nicotine content.

4. In the process of treating tobacco material to remove the nicotinecontent thereof, the step which includes the treatment of the tobaccomaterial by circulating in contact therewith an extractive agentcomprising water in the mixed liquid and vapor phase, while maintainingtemperatures to heat the tobacco to. volatilize portions of the water.

5. In the process of treating tobacco material to remove the nicotinecontent thereof, the step which includes the treatment of the tobaccomaterial with an extractive agent while maintaining a criticaltemperature for retaining the agent in the vapor phase, andintermittently subjecting the tobacco material to heating, varying froma temperature suflicient to volatilize the extractive agent to thatwhich is just suflicient to condense por- I tions thereof.

7. In the process of recovering nicotine from tobacco material the stepswhich comprise freein the nicotine content thereof by treatment with analkaline solution of water in quantities just below that at which thetobacco material will wad or chunk and subjecting thesame to heat,alternating from a high temperature to a low temperature, the hightemperaturebeing sufficient to volatilize the water and carrya quantityof nicotine. with it, the lower temperature being suflicient to permitcondensation of the steam without appreciable transfer of heat.

8. In the process of recovering nicotine from tobacco material the stepswhich comprise converting the nicotine content thereofto free nicotineby treatment with an alkaline solution of water in quantities just belowthat at which the tobacco material will Wad or chunk and subjecting thesame to heat, alternating from a high temperature to a low temperature,in an atmosphere containing steam, the high temperature be in"suflicient to volatilize the water to carry ofi a' quantity of nicotinewith it, the lower a temperature being suflicient to permit condensationof the steam without appreciable change of temperatureand continuouslyremoving the vapors containing nicotine from the zone in which they aregenerated.

9. In the process of recovering nicotine fromtobacco material the stepswhich comprise initially converting the nicotine content into freenicotine by treating with an alkali, adding water in quantities upwardsof but below that percent at which the tobacco material will wad orchunk -and subjecting the mixture to heat alternating from a hightemperature to a low temperature in an atmosphere containing water in topermit condensation of the steam without l appreciable change intemperature.

10. In the process of recovering nicotine from tobacco material thesteps which comprise freeing the nicotine content thereof y treatmentwith an alkaline solution of water in quantities upwards of 150% butbelow that percent at which the tobacco material will wad or chunk andsubjecting the same to heat, alternating from a high temperature to alow temperature, in a 3 counter-current of an extractive agentcontaining steam, the high temperature being sufficient to volatilizethe Water to carry off a quantit of nicotine with it, the lowtemperature l) sation of the steam without appreciable eing sufficientto permit conden- 3 change in temperature and recovering the nicotinefrom the extractive agent.

11. The process of treating tobacco material to remove its nicotinecontent which 3 to volatilize a portion of the water content,

to cooling suflicient to condense and absorb a portion of the extractiveagent and repeating the heating andcooling for alternate treatment ofthe first and second order to pro- I gressively remove the nicotinecontent of the tobacco material.

12. In an apparatus for extracting nicotine from tobacco material, aheating chamber, of means for progressively feeding raw material to saidheating chamber, and means for feeding an extractive agentcounter-currently to said material feeding means in said chamber, theextractiveagent feeding means including means for dispersing water infinely divided form, the chamber including shelves radially arranged insaid chamber and of a size and form to cascade the tobacco material fromthe peripheral walls towards the axial line of the chamber transverselyacross said current of dispersed water.

13. In an extraction apparatus of the character described, a heatingchamber, of means for progressively feeding raw material to said heatingchamber, means for counter-currently feeding an extractive agentcomprising water in finely dispersed form, radially disposed cascadingmeans for said material formed to progressively feed the materialtransversely across the current of said extractive agent and from theperipheral walls across the axial section of the chamber.

14. In an apparatus for extracting nicotine from tobacco material,aheating chamber provided with heating means substantially peripherallydisposed, means for feeding tobacco material progressively through saidheating chamber, means for counter-currently feeding an extractive agentincluding finely dispersed water adjacent the axial portions of saidheating chamber forming a cooler axial zone, and cascading means forsaid tobacco material radially disposed and formed to direct saidtobacco material continuously and progressively from the peripherallyheated portions of said chamber towards the axial zone across the pathof the current of the said extractive agent.

15. In an apparatus for extracting nicotine from tobacco material, arotary heating chamber provided with heating means substantiallyperipherally disposed in said chamber, means for feeding tobaccomaterial progressively through sa d heatmg chamber, means forcounter-currently feeding an ex-' tractive agent, including finelydispersed water adjacent the axial portion of said heating chamber,forming a cooler zone, and cascading means for gravitating the tobaccomaterial radially and transversely to the movemeans comprising radiallydisposed vanes.

16. In an apparatus for extracting nicotine from tobacco material, arotary heating chamber provided with means for heating the same, saidheating means being disposed substantially at the peripheral portions ofsaid chamber, means for mounting said chamber for rotation, means forfeeding the tobacco material progressively through said chamber, meansfor counter-currently feeding an extractive agent, adjacent the axialportions of said heating chamber, and cascading means forgravitationally forming a curtain of the tobacco material, transverselyto the movement of the extractive agent through said chamber, saidcascading means comprising radially disposed flat blades p0sitioned toextend from the peripheral portions across the axial line of saidchamber, and substantially free at said axial portions, whereby tobaccomay be cascaded substantially diametrically acrosssaid chamber duringits rotation.

17 In anapparatus for extracting nicotine from tobacco material, arotary heating chamber provided with means for heating the same, saidheatingmeans being disposed substantially at the peripheral portions ofsaid chamber, means for mounting said chamber for rotation, means forfeeding the tobacco material progressively through said chamber, meansfor counter-currently feeding an extractive agent, adjacent the axialportions of said heating chamber, and cascading means forgravitationally forming a curtain of the tobacco material, transverselyto the movement of the extractive agent through said chamber, saidcascading means comprising radially disposed, triangularly formed, flatblades positioned to extend from the peripheral portions across theaxial line of said chamber, and substantially free at said axialportions, and tapering in the direction of said axial portion of saidchamber,

whereby tobacco may be cascaded substantially diametrically across saidchamber and moved towards the exit end during its rotation.

In witness whereof, I have signed and sealed this specificfiation, thiseleventh day of December, A. D. 1925.

ROBERT GRAHAM MEWBORNE.

ment of the extractive agent, said cascading

